Invoking a response streaming enabled function using Lambda function URLs - AWS Lambda

Invoking a response streaming enabled function using Lambda function URLs

Note

You must invoke your function using a function URL to stream the responses.

You can invoke response streaming enabled functions by changing the invoke mode of your function's URL. The invoke mode determines which API operation Lambda uses to invoke your function. The available invoke modes are:

  • BUFFERED – This is the default option. Lambda invokes your function using the Invoke API operation. Invocation results are available when the payload is complete. The maximum payload size is 6 MB.

  • RESPONSE_STREAM – Enables your function to stream payload results as they become available. Lambda invokes your function using the InvokeWithResponseStream API operation. The maximum response payload size is 20 MB. However, you can request a quota increase.

You can still invoke your function without response streaming by directly calling the Invoke API operation. However, Lambda streams all response payloads for invocations that come through the function's URL until you change the invoke mode to BUFFERED.

Console
To set the invoke mode of a function URL (console)

  1. Open the Functions page of the Lambda console.

  2. Choose the name of the function that you want to set the invoke mode for.

  3. Choose the Configuration tab, and then choose Function URL.

  4. Choose Edit, then choose Additional settings.

  5. Under Invoke mode, choose your desired invoke mode.

  6. Choose Save.

AWS CLI

To set the invoke mode of a function's URL (AWS CLI)

aws lambda update-function-url-config \
  --function-name my-function \
  --invoke-mode RESPONSE_STREAM
AWS CloudFormation

To set the invoke mode of a function's URL (AWS CloudFormation)

MyFunctionUrl:
  Type: AWS::Lambda::Url
  Properties:
    AuthType: AWS_IAM
    InvokeMode: RESPONSE_STREAM

For more information about configuring function URLs, see Lambda function URLs.